Detainees are held at the facility during the day and then shuttled to local jails at night and on weekends, which the suit said "effectively cuts detainees off from contact with the outside world" and deprives them of basic needs.

"They are detaining people in inhumane conditions, grossly unsanitary and disgusting conditions," said Marisol Orihuela, a staff attorney at the ACLU. "There are serious violations of due process."

Immigration and Customs Enforcement authorities said they couldn't comment on pending litigation but issued a written statement saying that Department of Homeland Security Secretary Janet Napolitano has called for a comprehensive review of the nation's immigration practices and is committed to making "measurable, sustainable progress."

The department is "committed to providing secure, safe and humane treatment for all of our detainees," the statement said. "We are continuing to work with other agencies and stakeholders to improve services to those in our custody."

During a tour of the processing center last year, Eric Saldana, Los Angeles assistant field director, said the agency does its best to keep detainees there for just 12 hours at a time and quickly moves them to facilities designed for longer holding periods. Sometimes, however, he said detainees are kept longer or brought back for several days because of delays in accessing travel documents for deportation or limited space at local jails.

"Our goal is to get people out of here as quickly as possible," Saldana said.

The processing center holds up to 250. There are six large holding cells surrounding a central area with desks, where the detainees are photographed, fingerprinted and interviewed. Each has a phone, a bathroom and a bench around the edge. There are also smaller cells for families or juveniles. Saldana said detainees have access to medical staff and can ask to see a judge.

There are four named plaintiffs, but Orihuela said the lawsuit is on behalf of hundreds of detainees.

One of the plaintiffs, Russian immigrant Alla Suvorova, 25, said that for two weeks she spent every day at the center and every night at local jails. She was not able to get physical exercise during that time and was kept in a holding room where the toilet was consistently stopped up.

"It was terrible," Suvorova said in an interview. "They didn't give us soap. They didn't let me change clothes. They were transferring me from one jail to another."

Suvorova, married to a U.S. citizen but who overstayed her visa, said she also was not told whether she was eligible for bond. Yet when she was transferred to a facility in Washington state, she was released on bond at her first hearing. She is still fighting her case.

Another plaintiff, Mexican immigrant Abelardo Chavez Flores, 52, spent about a month and a half at the center, being taken to local jails most nights but also sleeping on the floor on several occasions. According to the lawsuit, he was held for 18 hours at a time in dirty and overcrowded rooms, denied access to a doctor and prevented from brushing his teeth for two weeks. He also wasn't given an opportunity to see his legal documents or file an appeal on his immigration case.

The plaintiffs have asked the court to order immigration authorities to set a time limit on detention or comply with detention standards, and to provide hygiene items, sanitary conditions, adequate sleeping facilities and access to legal materials.

"We just want them to follow the minimum standards guaranteed by the Constitution and the statutory rights the detainees have," Orihuela said.

anna.gorman@latimes.com